Precision-index



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H. U. WARREN.

PRECISION INDEX.

No. 531,817. Patented Jan. 1, 189.5.

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HERBERT C. VARREN, OF HARTFORD, CONNECTICUT.

PRECISION-INDEX.

SPECIFICATION forming part of Letters Patent No. 531,817, dated January1, 1 895.

Application filed April 11, 1 894.

To all whom it may concern:

Be it known that I, HERBERT C. WARREN, a citizen of the United States,residing at Hartford, in the county of Hartford and State ofConnecticut, have invented certain new7 and useful improvements inPrecision-Indexes',of which the following is a specification.

This invention relates to machines for the manufacture ofprecision-indexes, the object of the invention being to furnish animproved machine adapted for producing corrected or precision indexes ofthe class used on geareutting and graduating-machines, and forastronomical instruments and like purposes, with economy and rapidityand with the ntmost accuracy.

In the drawings accompanying and forming a part of this specification,Figure 1 is a plan view of one form of machine embodying my improvementsand adapted for carrying out my invention. Fig. 2 is a side elevation ofthe saine, the cutter for graduating or cutting the index-blank beingshown in an elevated position out of contact with said blank. Fig. 3 isa vertical longitudinal section taken inline 8-3, Fig. l. Fig. et is ahorizontal cross-section of a portion of the machine, taken in line 4-4,Fig. 3, a portion of the master-index being broken away to more clearlyillustrate certain of the details. Fig. 5 represents a table ofdetermined errors, showing the ascertained differences in plus or minusas between the approximately correct divisions of the masterindex andthe divisions of a correct, or precision, index.

Similar characters designate like parts in all the figures.

My improved machine for the manufacture of precision indexes, in thepreferred embodiment thereof herein shown, comprises a bed or frame-Workfor supporting the operative details of the mechanism, a Work-carryingspindle adapted for carrying a master-index and a blank from which acorrected or precisionindex is to be made, a master-index approximatelydivided into a given number of aliquot parts, each of which parts has aWorking face, a normally fixed reference point or scale, and a readingindicator in position and adapted for being shifted from and intobearing engagement with the successive Working faces of the masterindexand adapted to be read in con- Serial No. 507,133. (No model.)

neetion with said reference point or scale, all of which Will behereinafter more fully described.

In the drawings, the bed of the machine, which, in practice, may be ofany suitable form adapted for carrying the operative parts, isdesignated in a general Way by B.

The Work-carrying spindle, designated by S, is shown supported in abearing, 2, formed preferably integral with the bed or frame of themachine, aftera Well-known manner. The spindle S is shown provided witha Worinwheel, 3, rigidly fixed thereon in a manner hereinafter morefully described, whose teeth mesh with the threads of a Worm, 4, whichis carried by a shaft, 5, that is supported in bearings, 6 and 6', uponthe bed B of the machine. This worm-shaft is shown furnished with ahand-wheel, 7, whereby the same may be re- Volved for turning theWorm-Wheel, and through this the work-carrying spindle and parts carriedthereby.

In the form thereof herein shown, the worm- Wheel is connectedindirectly to the Workcarrying spindle, it being secured by means ofscrew-bolts to a master-index, C, which in turn is rmly secured to theWork-carrying spindle, preferably by being driven thereon. In thisconnection, it is desired to state that the master-index and theWorm-wheel secured thereto may be fitted to rotate upon the workcarryingspindle, and said spindle may be non-rotatively fixed in the bed orframe of the machine if desired, although the construction beforedescribed is preferable.

The master-index is herein shown as a discous plate radially dividedperipherally by a series of notches, S, to form a plurality of radiallydisposed workingfaces, 9, herein shown as twenty-four in number, thedifference between successive bearing-faces representin g approximatelyfifteen degrees and being designated, respectively, by the numerals l to24 inclusive. Said master-index has a hub, IO, of considerable length,which engages the Work-carrying spindle S and has a bearing at its lowerend upon the upper end of the journal-bearinlr 2. The master-index,which practically constitutes the pattern by means of which toapproximately position the index-blank for graduating or dividing, maybe constructed in any well-known man- 1 ner, and may .be divided intoany number of i laliquot parts, which will depend upon the,

f- After the master-index has been divided, as; justdescribedftoapproximate precision, saidy form of precision-index Ait is'desired'tomake'.y

index is measured yor surveyedl to accurately ascertain theerrorsindivision with relation l to aftrue standard,zwhich errors are then registered or tabulated in proper order with re#A lation tosuccessivedivisions of theindex to i designate'the/degree oreXtent oflerror, plus orminus, as compared with the precise divisi ion, Awhichwill be'y thoroughly understood by reference to'FigsAandofftheidrawings'.;

AThe method per se of surveying the index,- plate so as to obtain a truecorrection of rthe approximate divisions, is: well known in thel art towhich this kinvention appertains, and it is therefore deemed unnecessaryto enter into a detailed description of ythis method,

which, itmay be observed, is sometimesdes ignated lby inechanicians as,Troughtons methodl" 1 f' In practice, the indexdolank, designateiiy byD, will :preferably be: secured to the spindle' S abovetbe master-index,as illustrated lmosty clearlyin Fign of thedrawings, the said in-.manner to prevent accidental movement of lone part with relation to theother, the mas'-,

ter-index and worm-wheel being either keyed to or driven upon thespindle S, and the pre i n fcision-indexblanlr' rbeing fitted io rtheuppery yS5 i f by means of anut ..11, at the upper end thereof,

end of the spindleand securely held in place said index-blank D beingsupported at a suitable distance above the master-index by the hub 10 ofthe said master-index; or, these parts may be firmly fixed to theWork-carrying spindle by any well-known means for lixing wheels onshafts.

In connection with the foregoing, it is desired to state that thepositions of the masterindex and index-blank with relation to thespindle might be reversed, a corresponding re-arrangement of reading anddividing apparatuses being in such case made. The two plates or wheels,viz: the master-index and index-blank, should, of course, be rigidlyfixed or connected together preparatory to the operation of dividing orcutting said blank. This may be done by forming said two plates orwheels integral, by making them separate and rigidly fixing themtogether, or by making them separate and separately iixingeach one tothe spindle.

As a means for dividing, cutting or graduating the periphery of theindex-blank, especially when this is to have teeth cut therein after themanner represented in the drawings, I have provided a milling-cutter,l2, of a form suitable for cutting the required tooth-space; whichcutter is shown mounted upon an ordinary cutter-spindle, 13, that iscarried ina bearing, 14, upon a slide, 15, that is mounted upon verticalslide-ways,`16, formed upon a carriage, 17, which lis tittedforlhorizontal l movement in slide-ways, 18, formed upon the k'bed of themachine, as will be clearly understood by reference toFigs. 1y toy/iofthe draw-l ings.

said spindle may be driven through/the in'- tervention ofgearing after awell-known man `nerftor driving the cuttersof dividing-engines andgear-cutting machines. l l f For the purpose'of imparting to the cutter-Wheels the required kmovement laterally ofthe index-blank, thecutter-slide is yshown rpro- .vided with La screw-threaded projection orA pulley, 19may be fixed on said cutfter-spindle'asy shown in Figs. l, 2and 3; or,

nut,; 20, engaging with a screw, 21,15hat is can.

ried in a suitable bearing at the upper end of the. carriage i7',-asiliustratedmost clearly in Fig. 3, whiclfrscrevvl may be loperatedabyhand by means'y of the hand-wheel 22 secured y'to-said screw 2l;y andasa means for impartl inga movementgto the cutter toward and from: f

l2t? being provided. y.at-its outer Aendfwith a the axis of said blank,vI have provided a I screw, 23,-fjournaled at its outerend in a suit-lable bearing, 24:, upon the bed ofthe machine, I f f and having itsinner end Afitted in a screw.-

threaded opening, A25, in the. carriage 17, after l the well-knownlmannery ofk connecting feed; ing-devices with sliding carriages, saidscrew hand-Wheel, 26, rbymeans of which the screw l' may be revolved tofeed thecarriage toward orfro1n-thefwork.-f f l l f. f

As a means for supporting and holding the index-blank 'duringthe cuttingoperation,the

outeredge ofsaidwblank, :adjacent tothe point where the cutting .isdone,is lmade to bear upon a rigid support, 27, suitably ixed to a convenientpart of the machine,a clamp (not shown) being usually provided inconnection with said support -for clamping the blank thereon.

In the drawings, the master-index and its rotating-mechanism are shownprotected by a cover, 28, secured to thebed of the machine by suitablescrews; a supplemental cover or cap, 29, secured to the hub l0 of themasterindex, being provided to cover the slight opening at the top ofthe cover 28 and prevent admission ot' dust and dirt.

As a means for determining the position of the master-index, and as ameans for enabling the operator to bring the same'accurately to therequired position for making the graduations, I employ, in connectionWith the master-index and its operating means, a graduated readingindicator adapted for engaging the working-faces of the master-index andthereby showing with precision the location thereof. The graduated scaleot' said indicator, which will usually be a Vernier scale, constitutesthe reading-scale of the machine, the mode ot' usingwhich will behereinafter more full-y explained.

In the form thereof herein shown,the indicator, which is vdesignated inageneral way by L, is in the nature of a lever Vshown mounted upon apivot or stud, 30, fixed on IIO IZO

the bed of the machine. This lever has a tooth, or actuating-arm, 3l,located at one sidethereof in position and adapted for bearing againstthe working-face, as, for instance, the face designated by l, of themaster-index.

In the construction shown in the drawings, the indicator is actuated andcontrolled in its movements by the rotation of the master-index throughthe medium of the feeding-means in connection `with said index; but itis desired to state that said indicator might, with practicability,constitute a feed-lever for actuating or feeding the master-index, inwhich case the Worm-Wheel and Worm constituting the feed-mechanismhereinbefore described will be dispensed with, the indicator orfeedlever in this case being reciprocated to feed the master-index,together with the indexblank connected therewith, the requisite distancefor making the graduation. This reading indicator` will have itsindicating-end beveled to a knife-edge and provided with graduationsafter the manner of a Vernier; a reading-scale, 35, being employed inconnection with said indicator to indicate the position of themaster-index, as will be fully understood by reference to Figs. l and 4tof the drawings. The graduated scale 35 is shown as adjustably supportedin a slide-Way formed in a block, 36, upon the bed of the machine, andas provided with adjusting-screws, 37, by means of which the position ofthe scale may be changed as desired.

In operating the machine, assuming the actuating-arm 3l to be inworking-contact with a Working-face, as l, of the master-index, as shownin full lines in Fig. 4, the index is turned forward in the direction ofthe arrow in said figure, by means of the feeding-mechanism hereinbeforedescribed, which swings the indicator to the position shown in dottedlines in said ligure, with its actuating-arm in position to engage thenext succeeding working-face, 2, of said master-index; said indicatorbeing retracted or thrown into engagement with the successiveWorking-faces by means of a spring, 38, secured at one end to an arm,39, oppositely disposed with relation to the actuating-arm 31, andsecured at its opposite end to the block 36 or bed of the machine. Saidspring tends to normally retain the indicator with its operating-arm inconstant bearing-contact with a working-face of the master-index, and isof such a nature as to maintain a bearing-contact which will be ofuniform pressure, so as not to affect the precision of the reading,which might vary to some slight extent if the pressure of theactuating-arm 31 against the Working-face of the master-index shouldvary. This retraction of the indicator, it Will be understood, might beaccomplished to secure the same results bya weight or other suitableretracting-device.

In ascertaining the correct position of the master-index for marking thegraduations, the said index is moved until the reading of the indicatorcoincides with the required correctiondesignated by the Working-table Tof the respective working-face with which the actuating-arm of theindicator is engaged,

which working-faces are designated in the Working-table by the numerals1 to 24, inclusive, to coincide with the like designations in connectionwith the Working-faces of the master-index. For instance, in positioningthe master-indexv for making the first graduation, which is designated,alike in the working-table and upon the index, as l, the indicator isset with its operating-arm in contact with the Working-face l. Referenceis then made to the Working-table to ascertain the correction for therst graduation. In said table the iirst graduation is tabulated as1-.OOO1, which indicates that the correct position for the iirstgraduation is one tenthousandth of an inch less than that rst indicatedby the position of the indicator as determined by the reading-scale.Therefore the indicator Will be moved until the reading thereof willcoincide with the registered correction on the working-table, whichbrings the master-index to the corrected position for graduating ormarking the index-blank; which will be readily understood by thoseskilled in the art to which this invention appertains.

The indicator or feed-lever L herein shown and described is in thenature of a multiplier; and it is desired to state in this connectionthat I may substitute therefor any other Well-known fOrm of mechanicalmultiplier adapted for multiplying the indications of the apparatus.

Having thus described my invention, I claiml. In a machine for themanufacture of precision-indexes, in combination, a master-indexapproximately divided into a given number of parts, which parts eachhave a Workingface, a normallyr fixed reference-point or scale, and areadingindicator in position and adapted for being shifted from and intobearing engagement with the successive Workingfaces, of the master-indexand adapted to be read in connection with said reference point or scale,substantially as described.

2. In a machine for the manufacture of precision-indexes, a master-indexapproximately divided into a given number of aliquot parts, each parthaving a Working-face, in combination with an indicator in position andadapted for operatively engaging the successive Working-faces and havinga reading-scale, and means for changing the position of saidmaster-index, substantially as described and for the purpose set forth.

3. In a machine for the manufacture of precision-indexes, arevolubly-supported masterindex radially divided peripherally into agiven number of approximately aliquot parts, each parthaving aworking-face, a multiplier or indicator in position and adapted forsuccessively engaging said Working-faces, a reading-scale in' connectionwith said multiplier,

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and means for rotating the master-indexand for simultaneously changingthe reading-position of the multiplier, substantially as described andfor the purpose set forth.

4. In a machine for the manufacture of precision-indexes, incombination, a masterindex divided into a given number of approximatelyaliquot parts, each part having a working-face, an index-blank in rigidconnection with said master-index, a multiplier or indicator in positionand adapted for'successivel y engaging the Working-faces of themasterindex and having a reading-scale, means for shifting the positionof the master-index and the index-blank, and means for marking orcutting the grad nations or divisions upon the index-blank,substantially as described and for the purpose set forth.

5. In a machine for the manufacture of pre cision-indexes, thecombination with the framework, of a revoluble spindle, a masten indexsecured to said spindle and divided into a given number of approximatelyaliquot r parts, each part' havinga Working-face, anindex-blank in rigidconnection with said spindle and master-index, feeding-mechanism in`connection with said master-index, an indiw cater in position andadapted for successivelyY engaging the Workingfaces 0f the masterindex,a reading-scale in connection with the free end of said indicator, andmeans substantially as described for cutting or marking the graduationsin the index-blank, substan ially as described and for the purpose setforth..

6. In a machine for the manufacture of precision-indexes, arevolubly-supported masterindex radially divided peripherally into agiven numberof approximately aliquot parte and having a precisionindex-blank xedly connected therewith, in combination with apivotally-supported indicating-lever having an actuating-arm in positionand adapted for operatively engaging the successive Workingfaces of themaster-index, a reading-scale in connection with the indicating-end ofsaid lever, means for rotating the master-index to bring successiveWorking-faces into engagement withthe actuating-arm of theindicatorlever, a shiftablysupported cutter or marker in position andadapted for cutting or niarking the index-blank, and means for bringingsaid cutter into Working position with relation to said blank,substantially as described and for the purpose set forth.

7. In a machine'for the manufacture of pre cision-indexes, thecombination with the frame-Work, .of a master-index divided into a givennumber of, approximately, aliquot parts, each having a workiugface, anindexblank iixedly connected with said master-index and secured to arevcluble spindle, a Worm-Wheel secured to said master-index, a Wormmeshing with said Worm-Wheel, means for rotating said Worm, areading-indicator adapted for successively engaging the Working-faces ofsaid master-index, a cutter or marker revoluhly carried upon a slide inposition for cutting or marking the index-blank, and means for operatingsaid cutter or marker, substantially as described and for the purposeset forth.

` HERBERT C. WARREN.

Witnesses:

FRED. J. DOLE, FREDERICK A. ROLAND.

